Quadratic graphs sound hard…but they’re not really! They are simply just graphs in this format:
- y = x2 + anything
To plot a quadratic graph just put in a load of y values, and get the corresponding x values.
Once you have enough coordinates (usually about 9) you can draw the graph.
NOTE: it will be a smooth curve – if one point goes off you have made a mistake!
Here’s an example of what it should look like for y = x2 + 2x – 3:
Quadratic Graphs and Quadratic Equations
You may be asked to use a graph to solve a quadratic. For example solve the equation 0 = x2 + 2x – 3 using the graph y = x2 + 2x – 3 (shown above).
This is easy! Just look to see where y = 0 on the graph i.e. where the graph crosses the x axis.
So here you can see the answers are -3 and 1.